196 BOTANICAL GAZETTE [march 



chusetts, and eastern Canada. In general, the samples obtained 

 by probings were deep brown and plastic. They were fine and 

 uniform in texture, without large or fibrous inclusions. As the 

 topographical features around Lake Harris, in Florida, dispel any 

 doubt as to the allocthonous genesis of the stratum there found, 

 preparations from it will be discussed in detail. Fig. 1 represents 

 a sample taken from near the top, and a careful study of it shows 

 clearly pollen grains imbedded in an amorphous mass of drifted 

 and windblown floatsam, ejecta from water animals, etc. A 

 small spore may also be observed. Sponge spicules and idioblasts 

 from water lily stems likewise appear. 



A deposit very similar to the one just described was found 

 in Lake Dot, a small dumb-bell shaped body of water near Eustis. 

 This lake is very interesting as an example of those deep bowl-like 

 depressions, known as "lime sinks " (12), which are caused by a 

 subterranean solution of the underlying limestone, so that the roof, 

 becoming too thin to support its own weight, falls. Fig. 2 illus- 

 trates a section 3 feet from the top of a 9 ft. layer, and the characters 

 pictured were found by a study of the entire series to be uniform 

 throughout. It will be seen that this sample presents the usual 

 structureless material, ejecta, idioblasts, and pollen. In fact, 

 such structures as are usually encountered in lake "mud," but 

 absent from autocthonous deposits. 



The central layers of the peat in Lake Eustis furnished the 

 material shown in fig. 3, which shows several diatoms of the Stauro- 

 nesis and Navicula type, in addition to spicules from decayed fresh 

 water sponges. The section also shows 3 specimens of the amoe- 

 boid Arcella. Other features already found to be characteristic of 

 lake precipitations are idioblasts, pollen, etc. Fig. 4 represents 

 a sample of peat much like those just considered, except that there 

 are more plant fragments. The section from which this sample 

 was taken depicts the type of peat found in Lake Orange a mile off 

 shore, and the topography of the region, as well as the microscopical 

 structure of the material, shows it to be of undoubted lacustrine 



* 



origin. Although many other deposits throughout a wide range 

 were studied, these 4 illustrations are sufficiently characteristic of 

 all deep water formations, as well as the lower layers of bogs, to 



