54 
conclusions are, however, based upon too few data to be regarded as any- 
thing more than working hypotheses. 
The vegetation of the plain is modified profoundly by the salt springs 
that water parts of its surface. Where the soil surfaces have not had suffi- 
cient gradient to enable drainage lines to become established, shallow 
settling basins have collected thin deposits of saline materials from the 
spring outwash. In other places streams have carried off the outwash, 
leaving the surrounding soils with little or no salt. Thus there are two well- 
defined types of herbaceous vegetation on the plains: the first consisting 
largely of halophytic species, and the second of prairie species in an aggre- 
gate that somewhat resembles that of Peace point. 
The writer has made detailed studies (1928) at points about 16 miles 
southwest of Fitzgerald, in the vicinity of Heart lake, with additional notes 
along routes from this area to the Government Hay Camp and to Fitzgerald. 
The Salt Plains were crossed in 1929 between Salt River settlement and 
Little Buffalo river, and along the wagon road between Pine lake and Slave 
river. Figure 6 is a map made from aerial photographs in the vicinity of 
Heart lake. It is supplemented with diagrams of vegetational details 
(Figure 7) . 
Figure 7 shows a section of a dry watercourse and neighbouring prairie 
about 2 miles south of Heart lake. The creek probably has a spring flow 
which enters Salt river a short distance below" this point. The bottom of 
the creek bed has an open salt marsh vegetation which will be described 
later in connexion with the other halophytic types. The prairie is 
dominated by grasses that make a close turf. The area is nearly level 
and w r as very dry when the notes were made on August 20. 
Primary spp.: Agropyron trachycaulum var. unilaterale 
Koeleria cristata 
Secondary spp.: Juniperus horizontalis 
Hierochloe odorata 
Deschampsia caespitosa var. glauca 
Danthonia intermedia 
Schizachne purpurascens 
Agrostis scabra 
Populus tremuloides (saplings) 
Cerastium arvense 
Thalictrum venulosum 
Erysimum cheiranthoides 
E. parviflorum 
Ribes oxyacanthoides 
Geum triflorum 
Potentilla arguta 
P. Anserine 
Fragaria glauca 
Rosa acicularis (few) 
Vida americana 
Oxytropis splendens 
Linum Lewisii 
Galium boreale 
Symphoricarpos ocddentalis 
Achillea Millefolium 
Aster Lindleyanus 
