REPORT OF THE SECRETARY. 11 



was secured. It was necessary to do much heavy blasting to reach 

 the finest fossils which occur in the lower layers of rock. 



The collection of 1913 contains a number of very important addi- 

 tions to this ancient fauna and many fine specimens of species found 

 in 1912. A report on these collections is now in preparation. 



An illustrated account of my previous exploration in the Robson 

 Peak district was published in the Smithsonian Miscellaneous Col- 

 lections, Vol. 57, No. 12, and a paper with panoramic view, entitled 

 " The Monarch of the Canadian Eockies," appeared in the National 

 Geographic Magazine, May, 1913. Three other reports of my studies 

 were published in the Smithsonian Miscellaneous Collections, entitled 

 "New Lower Cambrian Subfauna," ^'' Dikelocephalus and other 

 genera of the Dikelocephalinae," and "The Cambrian Faunas of. 

 Eastern Asia." A report on " The Cambrian and its Problems in the 

 Cordilleran Region " is now in press in a new volume of the Dana 

 commemorative course at Yale University. The investigations dis- 

 cussed in this paper were continued in a report, " Pre-Cambrian Al- 

 gonkian Algal Flora," in the Smithsonian Miscellaneous Collections, 

 and preparations were made for further study of the subject in the 

 Rocky Mountains of Montana during the field season of 1914. This 

 was successfully carried out with the acquisition of several tons of 

 specimens. 



GEOLOGIC HISTORY OF THE APPALACHIAN VALLEY IN MARYLAND. 



Dr. R. S. Bassler, of the National Museum, spent a month during 

 the summer of 1913 in the Appalachian Valley of Maryland and the 

 adjoining States, studying the postpaleozoic geologic history of the 

 region, as indicated by the present surface features. His studies, 

 which were under the joint auspices of the United States National 

 Museum and the Maryland Geological Survey, were in continuation 

 of work carried on during the previous summer, when the sedimen- 

 tary rocks of the region were mapped in detail. 



Since Carboniferous times western Maryland has been above the 

 sea, and its rocks have accordingly been subjected to a long period 

 of aerial erosion. During Jurassic time the area remained stationary 

 for so long a period that the surface of the land in the Appalachian 

 province was reduced to a rolling plain. Later uplift raised this 

 plain still higher above sea level, and in Maryland only remnants of 

 the old surface are preserved in the flat sky line of the highest moun- 

 tains. This ancient plain, or Schooley peneplain, as it is termed, is 

 well preserved on the top of the Blue Ridge. 



A second great period of erosion occurred in early Tertiary times, 

 the effects of which were chiefly in the Appalachian Valley proper, 

 where the erosion is indicated by a pronounced plain at an elevation 



