SUBORDINATE GROUPS OR FORMA I IONS. 131 



The thickness of this formation seems to be very variable, and in 

 some districts it is represented almost entirely by conglomerates, 

 while in others it abounds in limestone and gypsum. It is very 

 largely developed in Hants and Colchester counties, and rises from 

 beneath the Millstone-grit in Cumberland, Pictou, and Cape Breton. 

 Smaller areas occur in several other parts of the province of Nova 

 Scotia, and it is extensively developed in New Brunswick. It affords 

 all the gypsum exported from Nova Scotia and New Brunswick. 



(e.) The Lower Carboniferous Coal Measures, or Lower Coal Meas- 

 ures. — In some localities these resemble in mineral character the true 

 coal measures. In others they present a great thickness of peculiar 

 bituminous and calcareous shales. They usually contain in their 

 lower part thick beds of conglomerate and coarse sandstone, which in 

 some places prevail to the exclusion of the finer beds. The charac- 

 teristic plants of these beds are Lepidodendron corrugatum and 

 Cyclopteris Acadica, with Dadoxylon antiquum, and Alethopteris 

 In trrophylla* They also contain locally great quantities of remains 

 of fishes, and many Entomostracans, among which are Leaia Leiilyi 

 and an Estheria, also Leperditia subrecta, Portlock, Beyrichia col- 

 ticulus, Eichw., and a Cythere,\ probably new. 



This formation is not everywhere distinguishable at the base of the 

 Carboniferous, and is variable in its characters. It is seen in southern 

 Cape Breton, in the county of Sydney, and in Hants ; but its most 

 remarkable and interesting exposures are at Horton Bluff and at Hills- 

 borough, and other places in southern New Brunswick. In the last- 

 mentioned locality, it affords the remarkable bituminous mineral 

 known as Albertite. 



The last two groups are probably equivalent to the " Sub-carbon- 

 iferous" of Western geologists; but independently of the objection to 

 the use of a term which would seem to imply a formation under, and 

 distinct from, the Carboniferous, and of undetermined age, I find in 

 Nova Scotia no reason, either palajontological or stratigraphical, for 

 any greater distinction than that implied in the term Lower Carbon- 

 iferous, by which these groups will collectively be designated in this 

 volume. The Lower Coal measures are, it is true, more distinct in 

 their flora from the Middle Coal measures than the latter from the 

 I pper Coal formation; but still many species are common to the 

 two former, and the difference is small as compared with that between 

 the Lower Carboniferous and the Upper Devonian. The Devonian 



* Dawson, " On the Lower Coal Measures," etc., Qnart. Journ. Geol. Soc., vol. xv. 

 p. 62. 



\ Prof. Junes of Sandhurst has kindly determined these species. 





