80 TRANSACTIONS OF THE [peEc. 16, 
Heavy crystalline beds :— 
Orthis ( Platystrophia) biforata. Monticulipora sp. 
(Dalmanella) testudinaria. Strophomena sp. 
Shaly partings :-— 
Crinoids aa a. Lingula ( Glossina) riciniformis. 
Acidaspis Trentonensis a a. larger form, also many frag- 
Orthis (Platystrophia) biforata a. ments. 
Monticulipora sp. a. Ptilodictya sp. 
Prasopora lycoperdon, large celled c. — Orthis ( Plectorthis) xquivalvis 
small celled c. subsequata. 
Rafinesquina deltoidea c. Plectambonites sericea, small form. 
Calymene senaria ¢. large ventricose form. 
Bryozoa. Strophomena planumbona. 
This total of 325 feet for the type section compares favorably 
with Walcott’s measurements at Utica,* twenty miles distant, 
where he obtained a thickness of 350 feet, including the Tren- 
ton, Black River and Utica. Vanuxemt+ estimated the thickness 
at Trenton Falls at “ upwards of 100 feet” only, while Darton 
states that “there appears to bea thickness of 120 feet. ” He says, 
however, that he made no careful measurement and that, “ owing 
to the dip of the beds down stream and the variability of the 
rate of dip, the total amount of fall is not a measure of the 
thickness.” MacFarland’s Geological Railway Guide§ says the 
formation is 500 feet thick and about seven miles in breadth. 
Miller’s Paleontology of North America|] says, “the limestone, 
at the falls is more than 100 feet thick.” 
The type section of the Trenton is not limited by other forma- 
tions at either extremity. The creek at Prospect has cut its 
way deep down into a narrow gorge, so that even the greater 
altitude of the creek level above Prospect Falls does not bring 
to light any layers higher than the crystalline beds capping the 
gorge section. North of here extensive drift deposits cover the 
country. The nearest occurrence of the Utica is at Nine Mile 
Creek, East Trenton, where it occurs in the bed of the brook, 
apparently faulted sharply against the Trenton, but affording 
no section, and too much covered by water for study at the 
season at which I visited the district (November).** The Utica 
here is a fine, rather thick bedded black shale affording Mono- 
prionid graptolites, often at least six inches long, Triarthrus 
Becki, Lepetopsis t and Orthoceras. ‘There i is s also said to bea 
* Proc. i x % Ss. XXXVL: : 212. 
+Second Annual Rept. of the 3d District (1838), p. 275. 
147th An. Rept. N Y. State Museum (1895), p. 619. 
¢Second Edition (1890), p. 118. 
| Fourth Edition (1 892), p. 40. ’ 
*C. D. WALCOTT: Trans. Alb. Inst. X: 18-23 (1883) described ten new species 
ted the ‘‘ town of Trenton.” 
