Is it legal for a sheriff to take my license because of speeding?

I am in Texas from Los Angeles, on business. I was driving on the freeway when I was pulled over by a local sheriff who said I was speeding: going 75 in a 65 mph zone. He took my license and said he could only give it back to me if I followed him to the local Municipal Courthouse and paid the $150 fine. Is this legal? I wrote them a check. What would happen if I put a stop payment on it? I go back to Los Angeles before the appear on or before date noted on the citation. I may never come back to Texas again but, could there be repercussions for me back in Los Angeles? I was not intoxicated.