Hopkinsʼ Plate 6. The upper drawing is a vertical section, and the lower drawing is the same, but cut horizontally. In Hopkinsʼ drawings, the massive coarse-grained Granite is progressively transformed from south to north; first to coarse-grained Gneiss with oriented minerals, and then to finer grained and more micaceous Schist. In modern geology we know that such changes can take place, but not in a south-to-north transition. From Hopkins (1844).

Contexts in source publication

Context 1

... shale. In some places (as e.g. near Purgono) the matrix is a dark-green silt, without any admixture of sand, but full of boulders of all sizes. Occasionally it is very fine in grain and sometimes assumes a shaley structure. A good instance of this, and one in which the boulder bed is seen resting on the gneiss, is shown in the accompanying Sketch (Fig. 4). [Fig. 19.] of a nullah section near the village of Kandusa on the Northern boundary of the field. The question naturally, indeed inevitably, suggests itself-How these enormous blocks of stone, manifestly requiring a great force to abrade and transport them, are found mixed with a sediment so fine, that in any, except a very sluggish ...

Context 2

... and, so far as known, the animals were of the same kinds as those of America. From this and other evidence it appears that the great northern continent Eria (Fig. 434) was still intact and was the land across which the plants and animals of Triassic time readily migrated to and fro. Crocodile-like reptiles of the sprawling type (Mystriosuchus, Fig. 458) and other active forms (Aëtosaurus, Pl. 31, Fig. 9) were common. Genuine turtles occur in the Triassic rocks, showing the group originated in the Permian. No lizards, snakes, or birds are as yet known in rocks of this ...

Context 3

... it has still not been translated to English. It had ten maps showing the positions of continents, climate indicators, and climate belts at different geological times. The maps were translated to English and published by Van der Gracht in 1928 (see p. 138). Köppen and Wegenerʼs first map, of modern climate belt and desert locations, is shown here (Fig. 40). The tropics are characterized by warm seas, abundant rainfall, and jungles. Note that desert sands and arid regions (dotted areas) are not found along the Equator, but in belts to the north and south of the tropics. This modern climate zoning must be understood before one can interpret the ancient climate zones. The simplest ...

Context 4

... paper had few sketch maps and geologic profiles, but they were intriguing. One map showed the close fit of continents in Gondwana, and the huge area of shallow marine sediments that would be shortened and compressed to form the Himalayas (Fig. 43, area c). And the profiles showed how mountain ranges formed by continental collisions (Fig. 44). But his paper must have been a disappointment. For some reason, his large colored map was not included and was totally unavailable to readers. This publication consisted largely of discussion of the rock patterns and the various folds of an unavailable ...

Context 5

... reproduced Wegenerʼs three globe maps as his Figure 163, and made very favorable comments. In a later section, Daly referred again to Wegenerʼs three maps, and followed them up with maps of his own, of the Atlantic (see Fig. 45) and the Pacific ...

Context 6

... geological time these have been regions of tension, not of horizontal compression. On the other hand, the Pacific should be, and is, well framed in mountain chains. In brief, the Atlantic and Pacific types of coast-line, fundamental features of the earth, are adequately explained by the hypothesis of the migration of continents. Figure 169 [ Fig. 45] is a map of the Atlantic basin with its great gulflike extension, the Arctic basin. The Circum-Pacific mountains of America are shown in solid black and are marked with the letter P. The east-west, older Hercynian-Appalachian system of the northern hemisphere is in part shown at I by axial lines. The slightly younger east-west system ...

Context 7

... involved in the formation of fold mountain belts. Glassy basalt, in solid form but without crystalline structure, would be quite ductile at high temperature. The lower parts of the crust could be removed as they plunge down into this ductile material, as the sediments and the upper part of the crust were folded and horizontally compressed (Fig. 46). The idea resembles subduction and formation of a melange of scraped-off sediments. We now know that the substrate is not basalt or basaltic glass, as Daly envisioned, but ultramafic rocks of the mantle. Although his working hypotheses were not completely correct, they were useful. They could have been improved, but no other North ...

Context 8

... on the other hand, the two land-masses are pictured as having been moved closer together, as in figure 7 [Fig. 47], a great number of observations and deductions are now found to be brought into apparent harmony, and these possible "coincidences" are disposed of in the simplest ...

Context 9

... volume was published in March 1928, 15 months after the symposium. The title of the book firmly established the phrase continental drift, rather than continental displacement. The North American authors were so critical of this theory that readers now considered it dead. The title page could have served as its tombstone (Fig. 48): Figure 48. The title page of the AAPG book that firmly established the term "continental drift." In the opinions of most North American geologists, it also laid this theory to rest. From Van der Gracht ...

Context 10

... North American authors were so critical of this theory that readers now considered it dead. The title page could have served as its tombstone (Fig. 48): Figure 48. The title page of the AAPG book that firmly established the term "continental drift." ...

Context 11

... this statement, Longwell used three printed pages, including two large and vacuous map figures (Fig. 49), to show that Australia could be forced-fit in the Arabian Sea between Africa and India. There is no geological matching of the African-Australian-Indian landmasses once they are fit together: Longwell 1928, p. ...

Context 12

... first important point Longwell made was that mountain belts are the result of horizontal compression. To illustrate this, he showed a laboratory experiment performed by Bailey Willis (Fig. 54). Longwell described some of the evidence that horizontal compression was the main force in the building of the Alps and other fold mountain ranges: Longwell 1929Longwell , p. 398-400 (also 1932Longwell p.398-399 / also ...

Context 13

... The maps were obviously outdated. They had few bathymetric contours and did not show the depth-sounding data that the contours were based upon. His detailed map of the Atlantic between Africa and South America had barely enough bathymetric detail to show the Mid-Atlantic Ridge. Dalyʼs modest map of the Atlantic Ocean from his 1926-book (see Fig. 45) had more detail. Willis may have been satisfied with his outdated maps, but the journal editors should not have accepted them in ...

Context 14

... to the north of this barrier (Figs. 1032, 1038). The Indian province was distinct from both the others. [Grabauʼs Fig. 1032 was a redrawn version On his paleogeographic maps he showed more information than others had done. He tried to indicate not only the coastlines, but also the locations of highlands, and the flow-directions of ancient rivers (Fig. 74), based on the preserved record of sedimentary deposits and fossils. Grabau's texts General Geology and Historical Geology were written for the same college market that the books by Pirsson and Schuchert were serving. This was stiff competition, and Grabau's books were printed only once. On the other hand, his earlier book Principles of ...

Context 15

... clouds were finally gone from the Atlantic coast on all three maps of Late Cretaceous time (Fig. 83). By then, Pangaea had broken up and the Atlantic Ocean had opened. For the three maps of Cenozoic time, no clouds were shown anywhere on the maps (Fig. 84). When Dunbar wrote that the clouds were "a device to hide critical areas" we can understand this as meaning a device to hide the ocean, which did not yet exist east of North America. Dunbar and Schuchert continually tried to hide evidence for mobilism in their writing and their ...