1896.] Laramie Mammah and Horned Dinosaur*. 119 



of the best skulls and skeletons found in these beds. Fossils 

 are found in both the shales and sandstones, but are best pre- 

 served in the latter. The small mammals are pretty generally 

 distributed but are never abundant, and on account of their 

 small size are seen with difficulty. They will be most fre- 

 quently found in what are locally known as " blow outs" and 

 are almost always associated with garpike scales and teeth, 

 and teeth and bones of other fish, crocodiles, lizards and small 

 dinosaurs. These remains are frequently so abundant in 

 "blowouts'' as to easily attract attention, and when such a 

 place is found careful search will almost always be rewarded 

 by the discovery of a few jaws and teeth of mammals. In 

 such places the ant hills, which in this region are quite num- 

 erous, should be carefully inspected as they will almost always 

 yield a goodly number of mammal teeth. It is well to be pro- 

 vided with a small flour sifter with which to sift the sand con- 

 tained in these ant hills, thus freeing it of the finer materials 

 and subjecting the coarser material remaining in the sieve to 

 a thorough inspection for mammals. By this method the 

 writer has frequently secured from 200 to 300 teeth and jaws 

 from one ant bill. In localities where these ants have not yet 

 established themselves, but where mammals are found to be 

 fairly abundant it is well to bring a few shovels full of sand 

 with ants from other ant hills which are sure to be found in 

 the vicinity, and plant them on the mammal locality. They 

 will at once establish new colonies and, if visited in succeeding 

 years, will be found to have done efficient service in collecting 

 mammal teeth and other small fossils, together with small 

 gravels, all used in the construction of their future homes. As 

 an instance of this, I will mention that when spending two 

 days in this region in 1893, I introduced a colony of ants in a 

 mammal locality, and on revisiting the same place last season 

 I secured in a short time from the exterior of this one hill 33 

 mammal teeth. 



Another way to secure these small teeth is to transport the 

 material to a small stream and there wash it in a large sieve 

 in the water, the finer material being washed away, but this 

 treatment is too harsh to give the best results, what few jaws 

 there are always being broken to bits. 



