The Levenshulme Limestones, 49 



small annelid, which probably lived and died quietly near 

 the spot. The Spirorbis has its like in the Serpidce now 

 living on our shores, feeding on seaweed. 



Another mottling, and that to which the workman's 

 name of " fish eye " more properly belongs, has a dark spot, 

 or nucleus, in the centre of each green spot; the grpen 

 fading gradually from the centre to the outside. The same 

 thing occurs in all the shales as well as in the limestones, 

 and especially so in the Permian red clays. I noticed in my 

 workshop when the tables were covered with slabs of red 

 marls, that the droppings of spiders and other large insects 

 discharged the red colour and left a circular whitish mark 

 permanently at the spot. This is, I believe, the explanation 

 of the " fish eye " mottlings. They are produced by copro- 

 lites. There are examples of these upon the table. One 

 of them shows in the centre of the dark nucleus a pink 

 spot, which indicates organic matter, — as it is generally 

 found hematite-stained in the limestone fossils. In the 

 uppermost limestone, where the pink colour is very slight, 

 coprolites occur as dull mottled circles, and in one of these 

 is to be seen a small tooth, quite visible to the naked eye, 

 and probably it will be found to have belonged to an 

 amphibian. There can be little doubt about these coprolites, 

 as a large number have been collected from the shales and 

 marls, as well as these occurring in the limestones. 



Returning to the simple green mottlings, which really 

 present to us the greatest interest, it will be found that they 

 are produced by organic remains, entombed in the lime- 

 stones. 



It is quite impossible to detect the delicate fossils which 

 produced them in a limestone fracture, even with the most 

 powerful lens, spirorbis you see at once, and green mottling, 

 but no trace of shells, so completely have they been absorbed 

 into the stone. 



I had a complete set of examples of the eight groups 



