STODDART, ON MICRO-GEOLOGY. 151 



just as they did in olden time^ as shown by the Bergmehl of 

 Sweden, the edil)le clay of the North American Indians, and 

 polishing slates of Bohemia and Africa. An exact counter- 

 part of the Calcaire grassier of the Paris basin is now in the 

 course of formation on the coast of Australia, a characteristic 

 fossil being the Orbitolite, which proves to be the same species 

 as that of France. All these will furnish hundreds of the 

 most beautiful slides, especially when mounted in balsam. 



No deep-sea soundings can be taken, whether Indian, 

 Atlantic, or Pacific, without the lead showing that the bottom, 

 whether of 60 or 2000 fathoms depth, is one entire mass of 

 the most exquisite forms of Polythalamia, Polycystina, Dia- 

 toms, or Spongiolites. The late soundings for the Atlantic 

 cable prove of great interest. Dr. Wallich's report has re- 

 vealed the fact that the Avhole floor of the ''true Atlantic,^' 

 which commences about 230 miles west of Ireland, is entirely 

 covered with a tenacious substance, nine tenths of which are 

 Foraminifera and Polycystina. In the Chalk, Foraminifera 

 are so well presei'ved, that when acted on with an acid, the casts 

 of the sai'codous bodies are seen as perfectly as the recent 

 ones of our own shores. These are also well seen in the dark- 

 coloured grains of the Upper Green Sand. 



Tripoli, which is an earthy-looking substance, is a good 

 example of the incredibly numerous microzoa that are present 

 in some of the earth^s strata. The bed in Bohemia from 

 which a sample was taken was fourteen feet in thickness, and 

 each cubic foot was calculated to contain more than forty-one 

 millions of Galliouella and other diatoms. 



The author has himself procured Polycystina from the 

 Barbadoes earth at the rate of more than ten millions per 

 avoirdupois pound. These beautiful little gems differ from 

 Foraminifera, not only in their nature, but also in having 

 siliceous instead of calcareous shells. 



Very beautiful microscopic objects are the fossil Chara 

 seeds ; they are found in the Tertiary strata of the Isle of 

 Wight, and, particularly under the binocular arrangement, 

 show the spirals in a very perfect manner. The author 

 has found three or four species, all of which are equally 

 good. 



Even this short and hasty sketch will show how true the 

 observation of Lamarck was, that it is by no means the largest 

 objects that Nature uses to produce everywhere the most 

 remarkable and astonishing phenomena. The remains of 

 minute animals have added much more to the exterior crust 

 of the earth than those of all the mammals and cetaceans that 

 ever existed. 



