Reports and Proceedings—Geological Society of London. 573 
consists of a thickened central axis with dorsal and ventral wings. 
The post-sacral connection is ligamentous. 
The proximal articular surface of the metatarsus has no inter- 
condylar process, but instead there is a shallow median groove 
which receives a ridge on the distal end of the tibio-tarsus, between 
the condyles. In the immature metatarsus, the fourth metatarsal is 
more weakly developed than the others, at least at the upper end. 
After an exhaustive comparison of the osteological characters of 
4Epyornis with those of the other Ratites, the author comes to the 
conclusion that the Aipyornithide constitute a distinct family, 
having no near relations, and being highly specialized and 
characterized by the massive structure of the skeleton accompanied 
by the pneumaticity of some of its parts. The resemblances with 
the Dinornithide he regards as superficial and merely the result’ of 
convergence due to similar conditions of life; on the other hand, the 
differences are considered to be of great importance, e.g. the pneu- 
maticity of the femur, which, among the Ratitze, occurs in 4/pyornis 
and Struthio alone. Siruthio also resembles ‘pyornis in some other 
respects, e.g. the structure of the egg-shell, so that on the whole the 
relationship between them is regarded as less remote than that 
existing between the Alpyornithide and the other Ratite families. 
In conclusion, it is suggested that the Dromaeide and Casuaridee, 
which, especially the former, are, in some respects, the least 
specialized Ratites, may be the recent representatives of a parent 
stock, from which, on the east, arose the Dinornithidx and Apteryx; 
while, on the west, the ancestors of Struthio and Apyornis branched 
off, the former making their way into Africa through India and 
Arabia, the latter reaching Madagascar by way of Southern India. 
Sevdsl pS (OS al Sy) e-IN(ID) JS tS4O) Seip sNierS 
——$—— 
GEOLOGICAL Society oF Lonpon. 
November 8th, 1893.—W. H. Hudleston, Hsq., M.A., F.R S., 
President, in the Chair.—The following communications were read : 
1. “The Geology of Bathurst, New South Wales.” By W. J. 
Clunies Ross, Esq., B.Sc., F.G.S. 
After sketching the physiography of the Bathurst district, the 
author describes in detail its stratigraphy. The oldest sedimentary 
rocks are Silurian, but the floor on which they rest is unknown, 
and the author states that it was probably fused up and incorporated 
in the granite which is described in the paper. The Silurian rocks 
may have been folded before the granite was erupted; in any case 
the granite produced a zone of contact-metamorphism, whilst almost 
all the Silurian rocks may be considered to be examples of regional 
metamorphism, though the agents producing the metamorphism 
were least active to the east of Bathurst, where the Silurian lime- 
stones are very little altered. An anticlinal was probably produced 
at the time of the granitic intrusion. After a time there was sub- 
sidence, but at first it need not have been very extensive, since 
