366 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



counties, and also in parts of northern Lancashire. In 

 the latter district other carboniferous rocks, including the 

 mountain limestone, appear, while in the extreme north 

 there is a mass of Silurian slate rocks. The Triassic 

 formations are in great part covered by recent boulder 

 c]ays and sands, which have filled the valleys and over- 

 spread the lower plains ; large peat mosses, now much 

 reduced by drainage and cultivation, also occur here and 

 there ; while along the western side are extensive tracts 

 of post tertiary silts, &c, covered again near the sea coast 

 by hillocks of blown sand. 



II. — Such geological features naturally produce much 

 local variety in the flora within the limits of our district. 

 The central plain is for the most part cultivated, and 

 therefore without marked feature ; the low hills and ridges 

 cropping up out of it are generally heath-covered or pine- 

 clad sandy tracts, with the plants peculiar to such 

 country ; and the same may be said of our peat mosses. 

 The limestone district of North Lancashire and the sand- 

 hill zone of our coasts each j)roduce highly specialised 

 floras ; and the' last-named, owing to lime from innumer- 

 able snail shells, also affords a home for many plants found 

 in the former. Further, the absence of rocks along our 

 shores ensures freedom from the salt spray so often 

 destructive of vegetation along a coast line ; so that for 

 several reasons our sandhill flora is particularly rich. 



III. — The mean annual temperature of the greater part 

 of our district ranges between 40° and 50° Fahr., or about 

 5° lower than Central and Southern England ; the mean 

 summer readings average 60° to 61° Fahr., or three to 

 four degrees less than the Thames Valley. 



IV. — The annual rainfall over the greater part of 

 Cheshire is 25 to 30 inches, about 5 inches more than the 

 eastern half of England, including the lower Thames 



