Geological Society. 229 



This structure, Mr. Austen states, agrees with that of the coral reefs 

 in the Southern Ocean, where the polypi raise their habitations on the 

 flat summits or sides of submarine hills, to a level with the surface of the 

 water. The stratified arrangement of the calcareous masses he consi- 

 ders may be explained by the occasional deposition of sedimentary mat- 

 ter, which might interrupt, for a time, the labours of the polypus ; and 

 thus a series of beds would be produced varying in thickness accord- 

 ing to the recurrence, at shorter or longer intervals, of interfering 

 agents, each bed rising successively to the surface level of the water. 

 If the deposition of sedimentary matter were great, then the polypi 

 would be destroyed, and the reef would become encased in a mecha- 

 nical accumulation. In further proof of the limestone of Devonshire 

 having been coral reefs, Mr. Austen adduced the great abundance of 

 zoophytes found on the surface of the lower strata, imbedded in the 

 layers of sand which separate the beds ; and, he added, that their 

 absence in other parts, especially in the interior of the bands, is no 

 objection to his view of the origin of the limestone, because, in re- 

 cent reefs, all traces of organic structure are frequently obliterated. 



May 9. — A communication by Dr. Black, F.G.S., was first read, 

 " On a fossil stem of a Tree recently discovered near Bolton-le- 

 Moor." 



The rock in which this fossil was found, occurs in the middle of the 

 coal-measures, about 50 yards beneath a six-feet bed of coal, and it 

 rests upon another bed four feet thick. It consists of three strata of 

 argillaceous sandstone dipping from 15° to 18° to the south-west, and 

 amounting in all to about 40 feet in thickness. The upper portion of the 

 fossil stem was discovered about thirty feet beneath the surface of the 

 rock, and the lower end extended to within 5 or 10 feet of the 

 subjacent bed of coal. It was inclined 18° to north-east, or in an 

 opposite direction to the sandstone strata ; and, when first laid open, 

 it appears to have been about 30 feet in length, but at the time it 

 was examined by Dr. Black only 12 feet remained in situ. The 

 upper end of this portion was 15 inches in diameter, and the lower 

 9 inches. The whole of the exterior of the stem was singularly 

 striated, and irregularly furrowed, as if by compression ; and it was 

 coated with a layer of coal, which evidently occupied the place of the 

 bark. The interior of the stem is stated to be composed of a dark, 

 hard, argillo-ferruginous sandstone, having a specific gravity of 2'9. 

 A Stembergia, about an inch in diameter, extended along the whole 

 length of the stem, and in some parts appeared to be half imbedded 

 in a groove in it. This connexion of the two plants was Dr. Black's 

 principal object in making the communication to the Society, not 

 having previously observed a similar occurrence, nor having heard 

 that it had been noticed elsewhere by other collectors. He is of 

 opinion that the Stembergia was not accidentally allocated wdth the 

 larger stem, but that it was, while living, a parasite, and in this 

 respect resembled the mighty creepers of the existing tropical 

 regions. 



A paper was next read, " On the Distribution of Organic Remains 

 in part of the Oolitic Series on the coast of Yorkshire;" by Mr. 

 Williamson, Curator of the Natural History Society of Manchester. 



