GEOLOGY. 315 



syenite, quartz, and occasionally of trap rock, tlie pebbles being but par- 

 tially rounded ; he had traced this deposite to a mountain of syenite and 

 green slate, fourteen miles to the west of north, known as Caledonia 

 Mountain. The coal basin of that region is made up of sandstone, 

 with limestone and white gypsum. Above this lies a richly bituminons 

 shale, soft, even flexible, filled with remains of fishes. Dr. Jackson 

 inquired if, in the widely-spread formation spoken of by Prof. Rogers, 

 there was any gradation of fineness in the materials, their fineness 

 increasing in proportion to the distance from their probable source, 

 indicating the action of the water rather than ice in their distribution. 



Prof. Rogers replied that such is the case. 



Dr. Jackson referred to the opinion of some geologists that the 

 Stigmaria are the roots of Sigillaria. From his own study of them he 

 still had his doubts of this. At the New Brunswick coal mines he 

 had seen the trunks of sigillaria imbedded in the rocks ; he had even 

 passed beneath them in the coal mines, and seen their roots branching 

 over his head, and they certainly were not Stigmaria. He had notic- 

 ed, also, in the centre of the markings of Stigmaria one and some- 

 times two little points. In the Mansfield coal mines he had seen 

 similar points in the adjacent rock. He was, therefore, inclined to the 

 belief that these markings are leaf scars. If the Stigmaria are roots, 

 then their rootlets must have been deciduous. 



Dr. Jackson mentioned the curious fact that, at the South Jog^gings, 

 immediately beneath the Sigillaria and coal, there are myriads of 

 fossil marine shells of a mvtiliform character. 



*/ 



ORIGIN AND COMPOSITION OF COAL. 



MR. TESCHEMACHER, has presented to the Boston Natural History 

 Society, some' additional observations* on the origin and composition 

 of .coal, with a view of showing the existence of coniferous plants in 

 the carboniferous period, as well as the general resinous nature of coal 

 of all descriptions. For this purpose he submitted the following 

 specimens. 



1st. A slice of Southern pine (pinus australis) in which, owing to 

 its resinous nature, the glandular vessels of the coniferous tribe are 

 very clearly visible. 2d. A slice of the same carbonized, in order to 

 show the appearance of these glands when changed by this action. 3d. 

 A specimen of anthracite and one of Cumberland coal, in which these 

 glandular vessels are extremely distinct. Such specimens are quite 

 common in Pictou coal. 4th. Impressions in the shale from Carbondale, 

 Pa., of the leaves of a species of pinus. 5th. A specimen of the same 

 shale showing an impression of the base of a bunch of leaves and its 

 sheath at the junction with the stem. 



On comparing the latter with the accompanying specimen of the 

 piuus australis of the present day, its close resemblance is very evi- 

 dent ; it fitting the impression almost as if moulded from it. On the 

 side of the recent specimen adjacent to the axis of the branch is a 



9 



* See Annual of Scientific Discovery, 1852, pp. 308 - 9. 



