200 



the unconformable position of the carboniferous series on the primary 

 Cumbrian slates, and the occasional masses of old red sandstone and 

 conglomerate by which, in the eastern part of the range, the two sy- 

 stems are separated from each other. 



Considered in its greatest generality, the carboniferous series is 

 divided into four groups: 1. The great scar limestone; 2, Alter- 

 nations of limestone, shale, and coal; 3. Millstone grit ; 4. Great 

 upper coal formation. The 1st and 4th preserve their characters in a 

 great measure unchanged in all the great carboniferous deposits of 

 England and Wales ; the 2nd and 3rd undergo modifications which 

 are briefly enumerated. In Flintshire, Yorkshire, and Cumberland 

 the richest metalliferous veins appear to be in the 2nd group. 



A paper was afterwards read, " On the occurrence near Shrews- 

 bury of Marine Shells of existing species in transported Gravel and 

 Sand, resting upon a peat bog which contains imbedded Trees;" by 

 Joshua Trimmer, Esq., F.G.S. 



In November of last year Mr. Trimmer noticed, that in widening 

 the road about five miles from Shrewsbury, towards Shiftnal, some 

 very black timber was extracted from beneath a bed of loam and 

 grave] ; and having subsequently examined the spot, he has commu- 

 nicated his observations in this paper. 



Two sections have been cut, to the depth of 15 feet, and are distant 

 from each other about 600 yards. The eastern excavation is 360 

 yards long, and consists, proceeding from east to west, of 200 yards 

 of sandy loiim and gravel ; 40 yards of sand resembling sea-sand, the 

 lamina crossing each other in various directions ; 60 yards of reddish 

 loam, with curved laminse near its junction with the sand, and hori- 

 zontal at the lower part, the upper portion not being laminated ; 

 and lastly, 60 yards of sandy loam and gravel. Fragments of shells 

 occur in every part of the section, but are most abundant in the veins 

 of fine gravel which pervade the sand : among them the author found 

 Turritella terebra, Cardium edule, and Tellina solidida. 



The western excavation contained fewer shells, and presented near 

 the eastern termination of the southern side : cultivated soil, 1 foot ; 

 whitish and reddish finely laminated loam, 6 to 8 feet ; peat, with 

 prostrate trunks of oak trees, 6 inches to 2 feet; black clay, 4 inches; 

 whitish sandy gravel, 12 to 18 inches, passing beneath the level of 

 the road into reddish sandy gravel. Still nearer the eastern termi- 

 nation, the section presented thin beds of laminated loam and sand 

 resting on peat. On the southern side this excavation consisted 

 of fine cultivated soil, 1 to 2 feet; sandy loam, with occasionally 

 boulders of several varieties of granite, some more than 2 feet long, 

 and patches of peat, containing fragments of oak, beech, and fir, 

 6 feet ; blackish loam, enveloping the upper part of a fir-tree, 6 

 inches ; peat, enveloping the lower part of the fir-tree, 2 feet : the 

 base of this tree was not visible, nor had anv trees still rooted been 

 noticed by the workmen. The patches of peat in the bed of loam 

 the author conceives were derived from the tearing up of part of the 

 peat bog. 



