https://github.com/ethereum/wiki/blob/c02254611f218f43cbb075...
From the block validation section: "Is block.timestamp <= now + 900 and is block.timestamp >= parent.timestamp?"
(In Solidity, block.timestamp is in seconds, and I think that's a direct translation from the underlying opcode, so I assume it's 900 seconds here.)
https://github.com/ethereum/wiki/blob/c02254611f218f43cbb075...
From the block validation section: "Is block.timestamp <= now + 900 and is block.timestamp >= parent.timestamp?"
(In Solidity, block.timestamp is in seconds, and I think that's a direct translation from the underlying opcode, so I assume it's 900 seconds here.)