1853.] 



DAWSON — COAL-MEASURES, NOVA SCOTIA. 



39 



the coal-swamps, as their remains occur in nearly all the bituminous 

 limestones and Modiola-shales. 



Two varieties of Cypris (figs. 29 & 30, ms.) occur. The more com- 

 mon variety is found in all the bituminous limestones and Modiola- 

 shales. 



The Spirorbis (figs. 31 a & b, ms.), so often found attached to 

 vegetable fragments, and which so frequently serves to mark periods 

 of submergence succeeding to those of vegetable growth, closely re- 

 sembles the Spirorbis carbonarius of the British coal-fields. 



Figs. 22 & 23 represent two species of the Modiolts, which swarmed 

 in incalculable numbers in the waters of the Joggins in the Coal sera. 

 These creatures were so extremely numerous, that many beds of cal- 

 careo-bituminous shale and bituminous limestone are almost entirely 

 made up of their shells ; and it is often difficult to find a shell not 

 crushed and distorted by the pressure of its neighbours. 



Figs. 24 & 25. — Uniones 

 from the lower Carboni- 

 ferous rocks of the South 

 Joggins. 



?. 24. 



Figs. 22 & 12>.—Modiol(B from the 

 coal-measures of the South Joggins. 

 Fig. 22. 



Fig. 23. 



Fig. 25. 



Figs. 24 & 25 represent a bivalve, perhaps a JJnio, not found in 

 that part of the section described in this paper. It was found by 

 Mr. Logan in a bed of bituminous limestone 3000 feet below our 

 lowest group, and associated with the lowest coal-seam but two in 

 the entire section. It is therefore peculiar to the very bottom of the 

 coal-measures, not being found, so far as I am aware, in any of the 

 numerous calcareous bands occurring higher up. It is associated 

 with Fish-scales and Cypris, and is separated by a great thickness of 

 beds from the marine limestones of the Lower Carboniferous series. 



Appendix. 



Abstract of Mr. Logan! s Section of the South Joggins Coal- 



Mr. Logan's section extends from West Ragged Reef to Seaman's 

 Bush, Mill Cove, a distance of about seven miles in a direct line. In 

 this space he found a vertical thickness of 14,5/0 feet of conformable 

 beds, which may be summed up as follows : — 



* First Report Geol. Survey of Canada. 



