21 



will bring you into correspondence with men of kindred tastes in all 

 parts of the world. The pleasure of making a collection is entirely in 

 the associations which centre around it, and the intercourse which is, by 

 its means, brought about with other students. Large numbers of 

 duplicates will always be accumulating ; these should be cai-efully 

 preserved for exchanging ; but, remember, as duplicates they are worth- 

 less to you, and never attempt to drive a bargain, or to get value for 

 value, but always strive to give more than you receive. It is better by far 

 to give away every specimen for nothing than to hoard them up to be 

 possibly desti'oyed by insects, or even to take up room which could be 

 better employed. Never send away a poor specimen ; of course, always 

 preserve the best specimen obtainable for your own collection, and if of 

 a species not represented, preserve even a very poor one until you get a 

 better, but after this send the very best you have to the first correspon- 

 dent who asks for it. If a specimen is too poor to send away destroy 

 it and get it out of the way. Never promise a rare species unless you 

 actually have it,or are positive you will be able to carry out your promise, 

 and, above all things, endeavour to gain a reputation for fair-dealing 

 and generosity. 



Note. — Tne following specimens, mentioned above, were exhibited : — 

 Specimens of Nuphar advena + Kalmiana, Caspary, and the two species N. advena, 

 and N. Kalmiana^ from which this hybrid is derived. A painting of the first 

 by Mr. W. H. 0. Watts. Two plants of the Fuchsia, one with the normal flower, 

 the other with the remarkable abnormality referred to above. Microscopic slides 

 of Psylla celtidis-mamma, Riley. A case of Hemiptera. A painting of Lewisia 

 rediviva by Mrs. Chamberlin. 



ON THE LAURENTIAN SYSTEM. 



Frank D. Adams, B.A.,-Sc. 



The Laurentian System is the oldest series of stratified rocks 

 which we are at present acquainted with on our earth. In whatever 

 part of the world we can extend our observations below the base of the 

 newer fossiliferous rocks, we find a great series of schists or slates, and 

 below these again a gi-eat series of various kinds of highly crystalline 

 rocks, gneisses, quartzites, etc., often with bands of limestone, and 



