38 
ASTRONOMY: C. D. PERRINE 
desert lands are accomplished. Neither feature is confined to areas 
which are situated at the mouths of canyons. Both are displayed in 
bajada belts where rock-floors are present and where the once even 
surfaces are worn out on the beveled edges of tilted strata. The Calico 
range, in the Mojave desert, north of Daggett, California, is a notable 
but not an isolated example. No eminence of the Great Basin region 
appears, at first glance, to be more certainly a 'lost mountain/ a lofty 
range buried up to its shoulders in its own debris. The bajadas on 
either side of the ridge all but meet over its summit. So low and 
rounded is the crest that manifestly there is no opportunity for exten- 
sive outwash around the borders. There is, in this instance, not only 
remarkable dissection of the bajada belt taking place at the present 
time but a widening of the apparent lines of drainage into wide flat- 
bottomed esplanades with deep reentrants. Elsewhere there is the 
anomaly of a long sinuous terrace several hundreds of feet in height sepa- 
rating the higher general plains-surface from the lower local plains-level. 
In this we get a glimpse of the formation of those heretofore inexpli- 
cable but characteristic desert features known as plateau-plains. In 
their last stage the isolated Towa-yal-lane, Acoma and Chupadera 
mesas, of New Mexico, are conspicuous illustrations. To this phase of 
the problem attention is later turned. 
The feature of desert bajada-terracing, when explained upon a strictly 
aqueous basis, cannot but lead to complete misinterpretation. The 
phenomenon has no necessary connection with former and greater 
stream-activity. It is one of the wide-spread characteristics of desert 
lands. It is far more largely the result of wind-action than of water- 
action. Its marvellous aspect is the great rapidity with which it takes 
form. It is, in reaUty, one of the subordinate expressions of regional 
eolation. 
RELATION OF THE APEX OF SOLAR MOTION TO PROPER MOTION 
AND ON THE CAUSE OF THE DIFFERENCES OF ITS 
POSITION FROM RADIAL VELOCITIES AND 
PROPER MOTIONS 
By C. D. Perrine 
OBSERVATORIO NACIONAL ARGENTINO, CORDOBA 
Communicated by E. B. Frost, November 27, 1916 
Continuing the investigation of the apparent dependence of the 
position of the solar apex upon proper motion as derived from radial 
velocities/ apices have now been derived from the proper motions 
