CHEBUCTO NULLIPORES—HONEYMAN. a8 
SUMMARY. 
Alge, coralline, foramenifera, sponges, serpule, spirorbis 
suaeicava, anomid. 
GEOLOGICAL. 
One specimen seems to throw some light on the mode of 
formation of one of our Carboniferous Limestones. In the Pictou 
carboniferous formation there is a considerable variety of lime- 
stones. Of the manner in which most of these were formed, 
and their age, there can be little doubt. The internal and 
collateral evidence is sufficient to determine these points. One of 
these limestones, however, is exceptional. Its mode of formation 
is obscure,—internal evidence of origin is wanting, and the age 
is subject to question. This limestone is imbedded in the 
sandstones, or high ground, north of New Glasgow. My atten- 
tion was first directed to it in 1862. Polished specimens were 
among the economic minerals of our department at the London 
Exhibition. It was considered to be a limestone, or marble, that 
might be adopted for ornamental purposes. It is brown in colour, 
and has a concentric structure. I took an early opportunity of 
examining the deposit, and of securing characteristic specimens. 
One of these, which is in the Museum, was polished by Mr. 
Wesley, marble worker, for the Paris Exposition of 1867. It 
was found that the bed was of limited extent, and that the sand- 
stone with which it was united interfered with the polishing. 
Another of the specimens, cut vertically, shows a sandstone 
base. On this there is first a calcareo-siliceous layer, which is 
amorphous. On this another is formed with several centres, 
above this it is beautifully concentric. The top of the specimen 
is cauliflower shaped. When Sir W. E. Logan and Mr. Hartley 
surveyed the Pictou coal fields in 1869, the latter examined the 
limestone, but was equally unsuccessful with myself in finding 
fossils which could determine the age of the formation. He 
succeeded, however, in finding one form,a spzrorbis. There was 
a large number of these attached to a specimen somewhat 
resembling our own, The appearance was so striking and singular 
