4G8 Reviews — Nicholson! s Essay 



is no doubt that we have certain flaggy beds at the top of the Grits, 

 with few fossils (Orthoceratitcs, Graptolites, etc.), the relation of 

 which to the lowest fossil-bearing Ludlow rocks has yet to be satis- 

 factorily made out. 



The author having noticed the two divisions of the Ludlow Eocks, 

 proceeds to point out that the highest Silurian Eocks seen in the 

 Lake Country are the Flaggy Grits of Benson Knot and Kirkby 

 Lonsdale. Above these there is an enormous break, perhaps the 

 greatest of which we have stratigraphical evidence in the whole 

 geological series. The Silurian rocks were crumpled up, cleaved, 

 heaved up into dry land, valleys were scooped out, and then the Old 

 Eed Conglomerate washed into those valleys ; hence it is now found 

 only in patches and pockets. Clearly this has nothing to do with 

 the red shales and sandstones which elsewhere succeed the Ludlow 

 rocks conformably. As the Carboniferous sea crept on, these con- 

 glomerates were overlain by other beds, either partly derived from 

 the same source as the conglomerates, or perhaps, partly composed 

 of those conglomerates re-sorted. In these plant-remains have been 

 found by Dr. Nicholson. It would, perhaps, be better not to call 

 these top beds Old Eed Sandstone. They are evidently a kind of 

 Basement Bed to the Carboniferous Limestone, and should the masses 

 of conglomerate turn out to be subaerial, it will be found to have 

 complicated the question to have assumed that these plant-bearing 

 beds are part and parcel of the irregularly disposed conglomerate. 



Our author then gives a short resume of what has been done in the 

 Carboniferous series, and passes on to a more detailed examination 

 of the Permian Eocks. The classification adopted is that of Pro- 

 fessor Harkness, whose views on the Geology of the Lake Country 

 generally, we may gather, agree on all important points with those 

 expressed in this Essay. 



The Permian Eocks are divided into three parts. The Lower 

 Permian consists of a great but irregular mass of breccia or con- 

 glomerate, succeeded by light red sandstones, and these again by 

 other breccias of a rather different character from those below. 



The Middle Permian consists of thin-bedded sandstones of various 

 colours and marly shales with plants, succeeded by impure magnesian 

 limestones and sandstones, above which come a set of red laminated 

 clays. 



The plants of the Middle Permian are very interesting. 

 " Though tolerably plentiful individually, they belong to few genera 

 and species, and they have a decided Permian facies, being specifi- 

 cally distinct from any true Coal-plants. It is worthy of remark 

 that the Coniferas now first produce true cones, thus differing from 

 the ' taxoid,' or berry-bearing forms of the Carboniferous Epoch," 

 p. 87. 



The Upper Permian consists of dark red fine-grained sandstones, 

 separated by courses of red shale. These beds were shown by Sir 

 Eoderick Murchison and Professor Harkness to succeed the Middle 

 Permian conformably and to pass into them, and on this ground 

 they are grouped with the Permian rather than with the Trias. 



