34 CONTRIBUTIONS TO THE GEOLOGY OF MAINE. [bull, 165. 
COBSCOOK BAY SERIES. 
Professor Shaler 1 has described an interesting series of Silurian 
deposits on the extreme southeastern coast of Maine, which contain 
faunas similar to those of the Ashland and Sheridan series of Aroostook 
County. The deposits resemble these series also in their association 
with detrital ash beds, lavas, and dikes, indicating disturbances of 
igneous origin during the Eosilurian period. Four distinct fossil- 
bearing horizons with their faunas are reported, as follows: 
Orange or Whiting Bay. — On the west side of Orange or Whiting 
Bay, about half a mile south of Balls Mills, in a very dense, much- 
jointed, siliceous limestone is contained the following fauna, which is 
correlated by the author with the Lower Helderberg; 
18. Rhynchonella mutabilis. 
19. Rhynchonella abrupta. 
20. Rhynchonella vellicata var. 
21. Rhynchonella formosa. 
22. Rhychonella sequivalis var. 
23. Rensselseria allied to R. oval is 
(doubful). 
24. Leptocoelia allied to L. fimbriata. 
25. Leptocoelia allied to L. concava. 
26. Atrypa reticularis (extremely abun- 
dant) . 
27. Orthis pedunculosa var. 
28. Orthis planoconvexa var. 
29. Strophodonta planulata var. 
30. Strophodonta beckii var. 
31. Trernatospira allied to T. deweyi. 
1. Orthoceras perstriatum. 
2. Orthoceras tenui-annulatum. 
3. Holopea antiqua var. 
4. Platystoma depressum. 
5. Platyceras lamellosum? 
6. Platyceras platystomum var. 
7. Loxonema allied to L. fitchii. 
8. Anatina sinuata? 
9. Avicula allied to A. manticula. 
10. Avicula allied to A. securiformis. 
11. Avicula allied to A. communis. 
12. Megambonia allied to M. lata. 
13. Megambonia allied to M. ovata. 
14. Spirifer modestus? 
15. Spirifer perlamelosus. 
16. Spirifer cyclopterus? 
17. Spirifer octocostatus. 
Dents Point. — At the head of Leigh tons Cove, about 2 miles to the 
northwest of Dents Point, in shales, generally thin bedded and con- 
taining but little lime, the following, which represent the Clinton and 
Niagara fauna in New York, are reported: 
1. Dalmanites limulurus. Clinton. 
2. Beyrichia symmetrica. Niagara. 
3. Orthoceras imbricatum. 
4. Orthis allied to O. elegantula. 1 As usual, these two forms blend together. 
* 5. Orthis allied to O. hybrida. | Niagara. 
6. Atrypa cuneata var. Niagara. 
7. Chonetes allied to C. cornuta, but much larger and with finer ridges. Clinton. 
8. Orbicula squamiformis var. Niagara. 
9. Lingula oblata. Clinton. 
10. Avicula allied to A. textilis. Lower Helderberg. 
11. Avicula emacerata. Niagara. 
12. Avicula rhomboidea. Clinton. 
13. Modiolopsis sublatus. Niagara. 
1 Preliminary report on the geology of the Cobscook Bay district, Maine: Am. Jour. Sci., 3d series, 
% Vol. XXXII, July, 1886, pp. 35-60. 
