CHAPTER II 



THE MICROSCOPICAL FAUNA 



OF THE 



CRETACEOUS IN MINNESOTA, WITH ADDITIONS 



FROM NEBRASKA AND ILLINOIS 

 (FORAMINIPERA, RADIOLARIA, COCCOLITHS, RHABDOLITHS). 



BY ANTHONY WOODWARD AND BENJAMIN W. THOMAS. 



I. METHODS OF MICROSCOPIC PREPARATION. 



The microscope of a few years ago, if compared with that now in use, was 

 of bat little practical value, and was regarded more as an amusing toy than as an 

 instrument of absolute necessity in scientific investigation. The geologist and the 

 botanist were apparently satisfied with their pocket lenses, and the physician had 

 but little use for 'even these. Careful students, however, were getting occasional 

 glimpses of fields just beyond their power of satisfactory resolution. These a some- 

 what more powerful combination of lenses would, to some extent, resolve, but would 

 at the same time show that there were much larger arid more interesting ones yet 

 beyond their reach. Scientists and physicians at once called for objectives of higher 

 powers, and for improved appliances, and manufacturing opticians of Europe and 

 America have promptly and satisfactorily responded to the demand. Excellent 

 instruments can now be secured at prices within the reach of every student. 



Geologists have long been familiar with fossil remains of pre-historic life, so 

 abundant in most of the geological formations, but it is of comparatively recent date 

 that impi'oved microscopes have shown them that of these vast deposits there is 

 hardly a cubic inch that does not contain the wreckage of an earlier world that 

 teemed with animal and vegetable life, and from which can now be studied its 

 history, climate, etc. These revelations are not infrequently of great commercial 



(23) 



