CLINTON GROUP. 



19 



Position and locality. In the central and lower part of the group at Blackstone's quarries 

 in New-Hartford, Oneida county*. (State Collection.) 



402. 7. BUTHOtREPHIS GRACILIS, var. INTERMEDIA. 



Pl. V. Fig. 2 a, b. 

 Fucoidis gracilis. Report of 4th Geol. District of New-York, 1843, p. 69. 

 Slender, flexible ; branches diverging, often simple and much elongated, of the same width 

 as the main stipe. 



It is difficult to draw any line of distinction between this and the preceding or the following 

 forms. Many specimens are slender and graceful, with few branches which often appear no- 

 dulose : other specimens are more rigid, and the branches numerous. 



Fig. 2 a. A slender specimen with few branches. 



Fig. 2 b, A more rigid specimen with numerous branches. 



Position and locality. Same with the last*, 



403. 8. BUTHOTREPHIS GRACILIS, var. CRASSA. 



Pl. V. Fig. 3 a, b, c. 



Plant flexuous, branching ; branches simple or bifurcating, more or less diverging from the 

 fcentral stipe, obtuse at the extremities, often nodulose. 



In the absence of definite characters, we are compelled to unite the three varieties of form, 

 which are most conspicuous, in one species. 



There seems to be a regular gradation of character through 1 c, 1 d, 2 a, 2 i, to 3 a and 3 b, 

 making it impossible to characterize distinct species. The smaller varieties are found in the thinly 

 laminated sandy shales which alternate with the coai-se irregular layers of sandstone and con- 

 glomerate : the coarse varieties occur generally in other beds of sandstone, less thinly laminated, 

 but composed of fine siliceous mud. This species is extremely abundant in the shaly sandstones 

 from Oneida county to the Genesee river, though it varies in form so much that scarcely two 

 specimens are precisely alike. 



In its general characters, this species resembles the B. subnodosa of the Hudso«-river group ; 

 but it is usually more delicate in form, and, in its mode of branching, differs from that one, 

 which is always somewhat nodulose. 



- Fig. 3 a, b, c, are common forms of this species in its stronger and coarser varieties. 

 Fig. 3 d. A large specimen, with the branches extremely diverging and mostly simple. 



{State Collection.) 



' This fossil reappears again in a western direction, far beyond the limits of New- York; but the lithological cha- 

 Iracter of the group has there entirely changed. 



