ON THE LEVENSHULME LIMESTONE. 125 



shown by the fact that the first young frog left the water 

 on the eighty-third day, and the last not until the one 

 hundred and third, or twenty days later. The influence 

 of temperature in hastening or retarding development has 

 no bearing on the present observations, the ordinary 

 spring temperature in which the ova were hatched pre- 

 senting no extremes which could produce perceptible 

 effects. 



XI. On the Levenshulme Limestone : a Section from Slade 

 Lane eastwards. By Wm. Brockbank, F.G.S. 



Read March 6th, 1883. 



The Permian strata around Manchester were favourite 

 subjects of study with our former President, the late E. W. 

 Binney, and his communications on them were frequently 

 laid before the Society and printed in its ' Memoirs/ To 

 Mr. Binney also were the Surveyors who mapped the 

 geology of the district for the Government indebted for 

 most of the information they used in laying down the 

 Geological- Survey plans of the Permian and Coal-measures. 

 This is acknowledged by Mr. E. Hull in his descriptions 

 of the geology of the country about Oldham, Bolton Le 

 Moors, and of the Permians of the Midland Counties. 

 "When, therefore, the Levenshulme limestones at Slade 

 Lane first came under my notice I at once referred to Mr. 

 Binney's papers, and found a section laid down about two 



