SMITHSONIAN EXPLORATIONS, I93O II 



Proceeding northward along the coast, the Boston Basin, one of the 

 classic geologic areas of America, was next in order. Here Doctor 

 Cushman pointed out the complicated structure of the Paleozoic rocks, 

 particularly the Roxbury conglomerate and the associated beds of 

 tillite. The origin of these two formations was much in doubt until, 

 in 1910, a resemblance of the tillite to present day glacial bowlder clay 

 was recognized by Dr. R. W. Sayles. This tillite, now known to be of 

 Upper Paleozoic age, is especially well exposed at Squantum Head 

 (fig. 9), the peninsula jutting out into the southern part of Boston 

 Bay. The outcrops here are of such interest that the area has been 

 presented to the city as a public park. Consequently no exhibition 

 specimens could be collected, but Doctor Sayles, who is much interested 

 in having a display of the conglomerate and associated bowlder clays 

 in the National Museum, holds out a hope that permission may be 

 granted for obtaining such an exhibit in the near future. 



Since two of the main building stones of our Natural Historv 

 building came from adjacent areas — the granite used in the construc- 

 tion of the basement from Mil ford, Massachusetts, and the white mica 

 granite used in the first and second stories from Bethel, Vermont, I 

 was naturally interested in spending some time in a study of their 

 characteristics and occurrence. 



Continuing north, other regions along the coast were explored, the 

 last being the Leda clay district of Maine where the possibility of 

 securing a considerable section of this interesting laminated clay was 

 investigated. 



On the return trip we took the route through the White Mountain 

 district and the peneplain area of lower New England, securing photo- 

 graphs illustrative of the physiographic development of these regions. 



Leaving New England, where we had enjoyed such pleasant associa- 

 tions and gained important geological information, Doctor Canu and I 

 proceeded to Washington. After spending several weeks together at 

 the Museum in preliminary work on our next bryozoan monograph, 

 several short trips were made to Atlantic Coastal Plain areas to study 

 at first hand the geological relationships of faunas under consideration. 

 Our particular interest lay in the bryozoan fauna of the so-called 

 Vincentown, New Jersey, marl, whose close faunal relation to the 

 Upper Mesozoic of Europe is most striking. Until recently this marl 

 has been regarded as marking the top of the Mesozoic era, but Ameri- 

 can students who have investigated the other classes of fossils of this 

 fauna and associated strata, now question the Cretaceous age of the 

 deposit, believing it to be Middle Eocene, a much younger formation. 

 As the Vincentown marl is at the boundary between two great eras of 



