73 
in ‘‘glacial” clay and at Ley land and Maccleslield in gravels. 
Neither of them had yet been recognised in the Blackpool 
beds, from which also a small collection was exhibited. 
January 19 th, 1874. 
Joseph Baxendell, F.B.A.S., Vice-President of the Section 
in the Chair. 
Mr. Percival exhibited specimens in fruit of Hypnum 
heterophyUum, gathered this month on wet rocks, Turton, 
near Bolton, a species which has very rarely been found in 
fructification. 
Mr. SiDEBOTHAM exhibited a specimen of silicious num- 
mulitic rock, from the banks of the Euphrates, the polished 
section of which exhibited the structure of the shells in a 
remarkable manner. 
Joseph Sidebotham, F.B.A.S., read a paper on “The 
similarity of certain Crystallised substances to Vegetable 
folms.” 
The author alluded to the many well known dendritic 
markings in shale and slate, which are often mistaken for 
sea-weeds and mosses, and to the leaf-like forms in various 
crystallisations. He then called special attention to some 
experiments carried on by the late Mr. Petschler and 
himself, on the crystallisation of bichromate of ammonia? 
nitrate of silver, and other salts, when in combination with 
gelatine and other colloid substances. The results of these 
experiments were brought before this society in the year 
1861, but so far as he was aware the subject had not been 
pursued further. 
