30 
Sphenoptems coralloides Gutb., Dictyopteris neuropier oidcs 
Gutb., Cyatheites villosus Bring., Cyatheitcs orcopteroules 
Gopp., and Alethopteris lonchitidcs Sternb., all true coal 
plants.”* 
No one more than the learned Author, I am sure, would 
like any mistake to be corrected. Now, in the statement 
that “ the reddish gray sandstone underlying it (the true 
Rothliegende), and which is very similar to the lower red 
sandstone of the north-east of England, contains plants of the 
coal measures,” the Doctor is quite correct ; but when he 
proceeds to state “ that it (the true Rothliegende) occupies 
even a lower position than certain limestones of the coal 
measures which are rich in ichthyolites,” the Author has 
misunderstood me by apparently confounding the ribbon 
beds of limestone in red marls lying above the pebbly beds 
at Astley with the upper carboniferous limestones at Ard- 
wick, and then stating that such pebble beds occupy an 
inferior position to the latter. It is certain that the Astley 
pebble beds containing coal plants occupy a higher geological 
position than the red shales which the Doctor truly states 
also contain true coal plants. How much higher it is 
impossible to say, as it is most probable there are higher 
carboniferous strata than those yet seen at Ardwick, and 
there may be permian strata lower than those up to this time 
met with at Astley — at present we cannot tell. 
As the permian group of strata is now occupying the 
attention of geologists both in England and on the Continent, 
the following table of the beds in the north-west of England, 
with their approximate thicknesses, as seen at Shawk, west 
ot Carlisle, Westhouse, south of Kirkby Lonsdale, and Man- 
chester, in the descending order, may be acceptable. 
* For the translation of this extract T am indebted to the kindness of 
Mr. Ekman. 
