22 



THE GEOLOGIST. 



passing downwards by insensible gradations into the old red 

 sandstone. 



Wednesday, l^th, November, 1841.— R.J. Murchison, 

 Esq., President^ in the chair. Professor Sedgwick continued 

 his remarks on the above subject, viz. : 



Old Red Sandstone.-^TYiQ extraordinary irregularity of this 

 formation in the British Isles is first noticed ; the old red 

 conglomerates of Cumberland are then com.pared with those 

 on both sides of the Galloway chain, and the sections in the 

 south of Ireland, connecting the old red sandstone with the 

 carboniferous series, and constituting a good passage, are 

 next described. The lower carboniferous shales there pass 

 into roofing slates, resembling the black slates at the base of 

 the Devonshire culm measures, and the great coal field, in the 

 west of Ireland, overlaying the mountain lime stone, assumes 

 the characters of the same culm measures. From the details 

 connected with the above statements, Prof. Sedgwick draws 

 the inference, that no nev/ formation can be interpolated be- 

 tween the old red sandstone and the carboniferous series, the 

 sequence of strata being complete ; and as the sections in 

 the Silurian country described by Mr. Murchison, show that 

 no member is wanting between the old red sandstone and 

 the Ludlow rocks ; there is, consequently, one continuous, 

 unbroken succession from the lower division of the new red 

 sandstone dovvU to the Llandeilo flagstone ; and, therefore, 

 that the argument for the true place of the Devonian system 

 is complete, for any formation with fossils, intermediate 

 between the carboniferous and Silurian systems must have 

 an intermediate position—must, therefore, be on the parallel 

 of some part of the old red sandstone, which fills that whole 

 intermediate position. 



Sections of North Wales, — The author, after referring to 

 his former description of the great masses of North Wales, 

 states that his Snowdonian fossils liave been found to be 

 identical with Silurian species, and that the same result has 



