252 NATURAL HISTORY. 



rocks are also desirable. The latter should be properly selected, and 

 cut to five by three inches of surface and one to two inches thick. 



The vertebrate fossils of North Ameiica are of the highest interest 

 to naturalists. These are found 'n fjreat abundance in those portions 

 known as "Mauvaises Terres," or ''Bad Lands," and occurring along 

 the Missouri and its tributaries, White River, Milk River, Platte, Eau 

 qui Court, &c. The banks and beds of these and other streams like- 

 wise contain rich treasures of fossil bones. Similar remains are to 

 be looked for in all caves, peat bogs, alluvial soil, marl pits, fissures 

 in rocks, and other localities throughout North America. 



The floor of any cavern, if dug up and carefully examined, will 

 generally be found to contain teeth, bones, &c. These, however simi- 

 lar in appearance to recent or domesticated species, should be care- 

 fully preserved. 



Specimens ought to be tightly packed up in boxes, taking care that 

 each one is wrapped up separately, in order that the angles or crystal- 

 line surfaces should not be destroyed by transportation ; their value 

 depending upon their good condition. The same precautions will be 

 required for corals. The interstices between the specimens in the 

 box or cask may be occupied by sawdust, sand, shavings, hay, cotton, 

 or other soft substance. It is absolutely essential that no cavity bo 

 left in the vessel or box. 



§ X. MINUTE MICROSCOPIC ORGANISMS. 



It is very desirable to procure specimens, from many localities, of 

 the various forms of microscopic animals and plants, not only on ac- 

 count of their intrinsic interest, but for their relation to important 

 general questions in physical and natural science. These will almost 

 always be found to occur in the following localities : 



1. In all light colored clays or earths, as found in peat bogs, mea- 

 dows, soils, &c., particularly when these are remarkably light. 



2. In the mud from the bottom of lakes and pools. A small hand- 

 ful of this mud or of the confervoid vegetation on the bottom, if diied 

 ivithout squeczmg, will retain the Diatomacea^ and DesraidiesB. 



3. In the mud (dried) from the bottom and along the margins of 

 streams in any locality. The muds from brackish and from fresh 

 waters will differ in thoir contents. 



4. In soil from the banks of streams. The surface and subsoils 

 should both be collected. 



5. In the soundings brought up from the bottom of the sea or 

 lakes. These should be collected from the greatest })ossihle dej)ths. 

 If an armature be used to the lead, it should be of soap rather than 

 fatty matter, as being more readily removed from the organisms. The 

 mud which adheres to anchors, to rocks, &c., below Idgh water mark, 

 as well as below loio water, should also be carefully gathered, 



G. In bunches of damp moss irom rocks, roofs of houses, trees, 

 about pumps, &c. 



7. In the de))osits in the gutters and spouting of roofs of houses. 



8. In the dust which at sea collects upon the sails or decks of vessels. 

 "When not in sufficient quantity to be scraj)ed off, enough may be ob- 



