EX-21 4 d33827exv21.htm SUBSIDIARIES exv21
 

Exhibit 21
SUBSIDIARIES OF THE REGISTRANT
     
    State of Incorporation
Name   or Organization
Amber Resources Company of Colorado
  Delaware
 
   
Piper Petroleum Company
  Colorado
 
   
Delta Exploration Company, Inc.
  Colorado
 
   
Castle Texas Exploration Limited Partnership
  Texas
 
   
DHS Drilling Company
  Colorado
 
   
Chapman Trucking Company
  Wyoming
 
   
PGR, LLC
  Colorado
 
   
CRB Partners, LLC
  Delaware