DAWSON GEOPHYSICAL CO

CUSIP: 239359102 Class: CMN

ESSEX INVESTMENT MANAGEMENT CO LLC's Holding History (CIK: 0000201772)

Note: Option positions (PUT/CALL) are excluded.

Q3 2013
Shares 21,683 Value ($000) $704 Avg Close — Range —
Q2 2013
Shares 28,571 Value ($000) $1,053 Avg Close — Range —