84 Prof. P. M. Duncan on Upper Silurian 



IX. — On some Spheroidal Lithistid Spongida from the Upper 

 Silurian Formation of New Brunsioick. By Prof. P. 

 Martin Duncan, F.R.S. 



[Plate IX.] 



In 1875 Mr. G. J. Hinde, F.G.S., sent a number of fossils to 

 the Geological Society with a short paper, which was published 

 in abstract*. He described them as coming from the cal- 

 careous shale of Lower Helderberg or Upper Silurian age in 

 New Brunswick, and felt disposed to classify them with the 

 Tabulata ; but he had not, at the time, the opportunity of amply 

 examining them. 



The spheroidal shape of the fossils and their evidently former 

 free existence attracted my attention a few weeks since, as I 

 was investigating the similarly shaped organic remains from 

 the Himalayas, which have been classified under the order 

 Syringosphajridas amongst the Rhizopoda. Mr. Hinde very 

 kindly allowed me to investigate the structure of the fossils 

 he had sent ; and this communication is the result of their ex- 

 amination. 



The four specimens of the spheroidal fossils which have 

 come under examination are oblate, symmetrical, rounded at 

 the top and bottom, and slightly produced at the equatorial 

 bulge. The heights are xV> t 6 o> tu i ncn 5 an< ^ the breadths re- 

 spectively 1-^j inch, 1 inch, and y 9 ^ inch. It would appear 

 that the growth was more in height than in breadth. The 

 fourth specimen had been polished on its poles and equator 

 in more than one place, and therefore could not be measured 

 correctly. 



The outside of the fossils is, where the organism has been 

 preserved, minutely granular to the eye, and is covered with 

 minute depressions between the granules. A low magnifving- 

 power shows that the granules are separate, rounded, minutely 

 irregular on their surface, about as high as broad, and that 

 the three or four which are round each depression are imper- 

 fectly connected by low and narrow processes. The granules, 

 however, are often broad and irregular, and form much of the 

 sides of the depression ; their general equality in size and 

 the vast number of the pore-like spaces included by them are 

 evident enough. 



In some places on the surface, where the weathering has 

 been greater, or where rubbing has removed more or less of it, 

 and especially at the edges of the abrasion, the bottom of the 



* " Description of a new Genus of Tabulate Coral. By G. J. Hinde, Esq., 

 F.G.S." Abstracts of the Proc. Geol. Soe., No. 305. * 



