LAG 
62. Homalonotus armatus Hall (rr). 
63. Ceramopora labecula Hall (rr). 
64. Stropheodonta profunda Hall (fragment). 
65. Pholidops ovalis Hall (interior of ventral valve). 
66. Fenistella parvulipora Hall (rr). 
67. Strophiodonta striata Hail (rr). 
68. Trematopora echinata Hall (rr). 
69. Stephanocrinus (fragment). 
70. Fistulipora maculata (Hall) (r). 
71. Crania sp. (rr). 
(The relative abundance of species in the above list is indicated by the letters. 
in parentheses, aa indicating very abundant; a, abundant; c, common; r, rare, 
and rr, very rare.) 
In the species Whitfieldella nitida no transitional forms were found between 
the large and small varieties, though a considerable number of specimens of both 
varieties were obtained. 
The form given by Hall as Lichenalia concentrica var. maculata is here re- 
ferred to the genus Fistulipora, since all the specimens from the present locality 
in which the macule are present, also possess mesopore apertures in the interaper- 
tural spaces, a character not possessed by Lichenalia as defined by Simpson. (See 
14th Ann. Rept. State Geologist of N. Y., p. 559.) 
THe SrrReAM GRADIENTS OF THE LowEeR MouAawk VALLEY. 
By Epcar R. CuMmINGs. 
During a recent study of the area mapped as the Amsterdam (N. Y.) 
sheet of the U. S. Geological Survey* the writer was struck by certain 
pecularities of the streams of this area emptying into the Mohawk River. 
As will be seen by a reference to the accompanying map, practically 
all of these streams have a relatively flat gradient throughout their upper 
courses. The streams A, D and F have not cut through the glacial till 
that forms the beds of their lower courses, while all the streams A, D, B, 
I’, G, H, flow over rock beds in their upper courses. 
*The results of this study dealing with the stratigraphy and paleontology of the Lower 
Silurian formation will be published as a part of Bulletin No. 32 of the New York State 
Museum. 
