360 CARNEGIE INSTITUTION OF WASHINGTON. 



rat-transect which runs for more than a half mile through the various 

 communities at the Alpine Laboratory. This is a soil quadrat 4 deci- 

 meters square, in layers of 2.5 cm., until a depth is reached at which no 

 organisms occur. Such a quadrat is primarily for the study of animal 

 organisms, as shown in the next section, but it serves also for the deter- 

 mination of algse and fungi in the soil. 



In successional studies, the tendency is increasingly to group quad- 

 rats in a transect running through the series of zones or commun- 

 ities. This permits the installation of quadrats in representative areas 

 as well as the mapping of community limits. A new method of photo- 

 graphing permanent areas and quadrats has been devised in which three 

 stakes are set in the ground in such manner as to record the exact posi- 

 tion of the tripod for future exposures. This method has also been 

 employed for recording the exact position of a group or community for 

 tracing the course of competition in grassland. A tilting tripod top 

 has been employed for taking views directly above plants and nests, 

 and it is hoped to develop this for the purpose of taking overhead views 

 of quadrats of many kinds, in lieu of charting them. Various improve- 

 ments have been made in the manner of staking quadrats, new tapes 

 have been devised, and a larger form of chart has been developed to per- 

 mit greater minuteness of detail. 



Soil Fauna of Engelmann Canyon, hy G. W. Goldsmith. 



A qualitative and quantitative study is being made at points across 

 Engehnann Canyon to determine the relation of the fauna, to soil 

 conditions and plant cover, and the biotic correlations. At the place 

 chosen for the work, the canyon runs approximately east and west, 

 the walls being about 500 feet high. Since a careful survey of the vege- 

 tation has already been made by means of a transect, and the eleva- 

 tions and distances accurately mapped, all the soil quadrats are located 

 in this transect. A soil quadrat, 2 dm. square, is located in each typi- 

 cal community and the soil to a depth of 2.5 cm. is quickly removed 

 and placed in a waxed paper-bag. The soil is then removed succes- 

 sively from similar layers to a depth of 2 dm. and the whole brought at 

 once to the laboratory for examination. At the tune of each collection, 

 the temperature of the air immediately above the soil, and of the soil 

 at 2.5 cm. and 2 dm. was taken. Samples of the layers were also 

 taken in duplicate and used for determining the water-content and 

 ignition-loss as well as for mechanical analysis. The bagged material 

 is carefully sifted through a screen with 6 meshes per inch and then 

 through a second screen with 14 meshes per inch. After each sifting 

 it is spread in a thin layer over a white oilcloth and kept for several 

 minutes under close observation. The animals found are collected 

 by means of the forceps and a brush saturated with glycerine, and are 

 placed in 50 per cent alcohol. When no more animals are visible, 



