i8z REMINISCENCES OF 



old friends, Professor Schimper of Strasburg, who 

 introduced into his well-known " Paleontologie Vege- 

 tale " a large number of genera and species of these 

 questionable objects. 



Schimper's example has still more recently been 

 followed by the Marquis de Saportaof Aix. The deter- 

 minations of the latter author have been vigorously 

 controverted by Professor Nathorst, who tried a num- 

 ber of very important experiments resembling those 

 made by Professor Buckland many years ago, when 

 the reptilian footsteps of Corn-Cockle-Muir were 

 first discovered and their nature much debated. 

 Professor Nathorst made various aquatic animals 

 travel under water, leaving behind them, as they 

 did so, very definite tracks on fine mud, and he 

 published photographs of these tracks, so that no 

 artistic errors could creep into his figures of them. 



In 1885 I received from the Rev. Isidore 

 Kavannah, of Montreal, then a student of the 

 Roman Catholic College of Stonyhurst, in Lanca- 

 shire, some interesting specimens which he had 

 discovered upon loose blocks of stone strewing the 

 shore of the Ribble, close to the college. The 

 bank of the stream at this point is composed of 

 what are known geologically as Yoredale rocks, a 

 series of beds that intervene between the millstone 

 grit and the mountain limestone. 



The controversy between my two friends, Saporta 

 and Nathorst, illustrated as it was by the beautiful 

 objects obtained from Stonyhurst, led me to give 



