424 GEOLOGICAL NOTES 



the vanishing outlines of the pebbles of the conglomerate. In the 

 last-mentioned case at all events the author is now confident 

 that the phenomenon is due to the laccolite of quartz-porphyry 

 attacking the conglomerate and dissolving and partly replacing 

 the more fusible portions of it, which would chiefly be its base, 

 whereas its less fusible portions, such as pebbles of quartzite, 

 would still remain unfused, though in many cases completely 

 surrounded by the quartz-porphyry. A further investigation of 

 these metamorphic conglomerates will, the author feels confident, 

 lead in some cases to the adoption of the theory now put forth to 

 account for their origin as being probably nearest the truth. 



(2.) Note on the occurrence of Glossopteris in a remarkable 



STATE OF preservation IN THE GrETA CoAL-MeASURES AT 



Richmond Vale near Maitland. 



So far as the author is aware, Glossopteris h?L?,\\it\\Q\to been met 

 with in the fossil state either in the form of casts or impressions, 

 the original carbonaceous material having completely disappeared, 

 or in the form of carbonaceous material representing the original 

 vegetable matter of Glossopteris, but structurally much altered. 

 Recently, however, the discovery has been made of Glossopteris 

 leaves, in only a slightly altered condition, in the clay shales of the 

 Greta Coal-Measures at Richmond Vale, twelve miles southerly 

 from Maitland. A large shaft has been sunk here by the Rich- 

 mond Vale Syndicate, which at a depth of about G90 feet (the 

 shaft throughout to that depth being in the Upper Marine Series 

 containing an abundant Permo-Carboniferous Maiine Fauna) 

 struck the first of the Greta Coal Seams ; at 22 feet (about) below 

 the first seam a bed of grey sandy shale was passed through, 8^ 

 feet in thickness, the upper portion of which contained layers of 

 Glossopteris leaves in great abundance. The leaves occur matted 

 together in layers from ^ of an inch to \ inch thick. Owing to 

 the great pressure to which they have been subjected it is a matter 

 of considerable difiiculty to disentangle any individual leaves from 



