246 Scientific Intelligence. 



plains, and we have made some progress in correlating these 

 events. 



" We have also found full confirmation of the statements as to 

 a progressive desiccation of the region of long standing, which 

 has from a remote period continually converted cultivable lands 

 into deserts and buried cities in sands. 



" We have found, widely distributed, great and small aban- 

 doned sites of human occupation, with evidences of great 

 antiquity. 



" We have reason to think that a correlation of these physical 

 and human events may be obtained through a continuance of the 

 investigation, and that archeological excavations will throw light 

 on the origin of Western and Eastern civilization." 



In the second article Professor Davis describes his observations 

 upon the Caspian region with its abandoned shore lines up to 600 

 feet above the present water-level, and the traces of the Pliocene 

 sea whose deposits, as the Russian geologists have shown, under- 

 lie the plains of southern Turkestan. He says of the Piedmont 

 plains that : " Since the withdrawal of the Pliocene sea, the eastern 

 and southern borders of the plains of southern Turkestan appear 

 to have been aggraded by the rivers that flow out upon them 

 from the mountains. That a certain measure of such construc- 

 tive action has taken place is announced by the Russian geolo- 

 gists, but it is not apparent that the full measure of river action 

 has been recognized. Some of the strata of the plains are said 

 to be not fluviatile but lacustrine, because they are. of fine texture 

 and uniform structure, without the variable layers of gravel that 

 are by implication supposed to be always indicative of river 

 work; but this seems to be a simpler solution than the problem 

 deserves. There are many rivers that do not carry gravel, and 

 there are many river plains whose smooth surface must receive 

 very even and uniform deposits of flood-laid silts over large 

 areas. Records of boring are quoted by Walther which show 

 river muds on sand and loess to a depth of nearly 50 meters 

 beneath the bed of the Amu River at Charjui, where the 

 great railroad bridge was built. The record of a well boring 

 at Askhabad, quoted by the same author, shows variable pied- 

 mont deposits over 2,000 feet deep. It seems, indeed, as if we 

 had in the plains of Turkestan and the Great Plains of our 

 West one of the most striking of the many physiographic resem- 

 blances between Eurasia and North America; and that there as 

 w r ell as here an increasing share may be given to the action of 

 aggrading rivers in forming the plains, as observations are 

 extended. It is well known that the tide of geological opinion 

 in this country has in recent years turned more and more toward 

 a fluviatile origin for the strata of the Great Plains that slope 

 eastward from the Rocky Mountains, and the traditional lacus- 

 trine origin of the plains strata has been repeatedly questioned ; 

 so we may expect, as closer attention is given to the details of 

 river-laid formations, that a larger and larger share of the fresh- 



