24 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 2, 



sedimentary deposits. The lower part presents the usual succes- 

 sion of underclays, coals, and shales ; and two of the coals contain 

 well-preserved remains of the plants {Siyillaria, Poacites, &c.) 

 which grew on their underclays. The highest coal of this group 

 has undergone a temporary submergence, as its upper part con- 

 tains Poacites covered with Sjnrorbis. That this submergence was 

 not without mechanical deposition, is shown by the preservation in an 

 erect position of several Calamites which grew on the surface of the 

 coal. On the clay next deposited grew a furrowed tree, with Stig- 

 m aria-roots (like that of fig. 13, ms.). This surface was buried under 

 the irregularly-bedded mass represented in fig. 1, and the probable 

 origin of which has been already referred to (p. 13). The surface, 

 having been levelled by these deposits, was again occupied by forests 

 of the Stigmaria-rooted trees, the only remains of which are an under- 

 clay, somewhat arenaceous, and a thin layer of impure coal with 

 flattened carbonized trunks. On this prostrate forest a thick bed of 

 clay was deposited, on the surface of which grew the finest Calamite 

 brake now remaining in the section. These Calamites are, as usual, 

 stony casts, and they are buried in a thick bed of sandstone passing 

 downward into arenaceous shale. The largest stems are 5 inches in 

 diameter, and attain a height of 8 feet, when they are broken ofl" 

 without any diminution of their diameter. They grew in groups or 

 clusters, and were so numerous, that, in one place, twelve stems were 

 counted in 8 feet measured along the face of the chfF. From the 

 base of the cliflF to the level of low water, 120 paces distant, they 

 were observed to occur abundantly. Part of this bed is shown in 

 fig. 5, MS., where three groups are seen, the individual stems con- 

 verging toward the base, and terminatmg in blunt points, as in the 

 case of the bed of erect Calamites at Pictou, described by the vniter *. 

 Fibrous roots, probably those of the Calamites, occur in the under- 

 lying shale. 



The beds last noticed curiously mdicate the different ways in 

 which the lapse of geological time may be marked. The sandstone, 

 8 feet in thickness, enveloping the Calamites, must have been depo- 

 sited in a year or two. A layer of coal, 2 inches thick, is all that 

 marks the growth and decay of a forest. 



The XXth Group is a series of sandstones and shales, with three 

 underclays. The shales are mostly chocolate-coloured, and the 

 sandstones grey and irregularly bedded. 



The XXIst is a succession of swamp-deposits, with a few barren 

 intervals, but presents nothuig suflaciently novel to detain us. 



The XXIInd is a rather barren group, containing however erect 

 plants at two levels. The lowest of these has both ribbed stumps 

 and Calamites. The latter present evidences of extreme decay. The 

 bark has not retamed its cylindrical form, but has fallen inward in 

 strips, leaving a rude cylindrical cavity now filled with clay-ironstone 

 and shale. 



Group XXIII. is the most important continuous series of swamp 

 and estuary deposits in the section, and includes the coal-seam at 

 * Quart. Journ. Geol. Soc. vol. vii.p. 195. fig. 1. 



