298 Mr. Brockbank and Mr. C. E. de Range on 



were first described by Prof. Phillips in 1836. He was the 

 first to recognise the Spirorbis^ and he recorded the discovery 

 of the Megalichthys Hibbertii in these beds. A fine set of 

 Ardwick limestones with scales of this large fish is in Peel 

 Park Museum, and a large slab of the same is now before 

 us ; it is of this piebald stone ; the pink portion is full of 

 Spirorbis and dotted over with large scales of Megalichthys^ 

 whilst the other portion is of the blue limestone, covered 

 with shells, amongst which are the Anthracomya above 

 referred to. We have had thin sections cut from the two 

 varieties in this Ardwick limestone, and under the microscope 

 they are almost identical with our No. 6 Group, the same 

 shells, bones, ^;/^^w^j/r^r«, colours, and the general agreement 

 being undeniable. Here, then, we appear to have a datum, all 

 the groups from Nos.i to 5 inclusive being above the Ardwick 

 limestones of Prof. Phillips, Mr. Binney, and Prof Williamson 

 and Nos. 6, 7, and 8 being the old Ardwick beds, as they 

 reappear slightly different in thickness, etc., at Levenshulme. 

 The piebald colours in this group are very peculiar, and 

 not easily to be accounted for, neither is it easy to account 

 for the extreme irregularity of the beds. The only separa- 

 tion between No. 6 and No. 7 Group is a band of reddish 

 marl, loin. thick. 



yth Group of Limestones. 



ft. in. 



(i) Limestone ... ... ... ... o 85^ 



Bright green marl ... ... ... o 2 



Compact hematite red marl ... ... o i 



Earthy ironstone — olive brown ... o 2^ 



Purple marl ... ... ... ... o 3 



Calcareous nodules in yellow marl ... o 6 



Purple marl ... ... ... ... i o 



(2) Limestone, very rough, lumpy with 



purple fracture ... ... ... i 3 to i*6 



Green marl ... ... ... ... o 2 



Purple marl ... ... ... ... o 4 



Green and red marls ... ... ... i o 



Dark purple and grey marls ... ... 2 o 



^3) Limestone fish bed ... ... ... o i 



Green marl ... ... ... ...04 



I 



