Mr. Jenner. And how long have you held that position?
Mr. Mamantov. Since 1955.
Mr. Jenner. And is that your profession—a geologist?
Mr. Mamantov. That's right.
Mr. Jenner. And prior to 1952, your employment was?
Mr. Mamantov. With the Donnally Geophysical Co. here in Dallas as seismologist.
Mr. Jenner. And over what period of time did that work extend?
Mr. Mamantov. It covers 1951, the summer of 1951 until the fall of 1955, when I took my present job.
Mr. Jenner. Let's take one step back—by whom were you employed, or with whom were you associated, prior thereto?
Mr. Mamantov. Lion Match Co.