l1f1.dat
First Record: 124:10:39:42::     Last Record: 124:10:45:33::

There are no lines 2-6.

l7f1.dat
First Record: 124:12:54:15::     Last Record: 124:13:21:43::

l7f2.dat
First Record: 124:13:21:44::     Last Record: 124:14:11:31::

l7f3.dat
First Record: 124:14:11:32::     Last Record: 124:14:50:49::

l8f1.dat
First Record: 124:14:50:50::     Last Record: 124:15:21:19::

l9f1.dat
First Record: 124:15:38:02::     Last Record: 124:16:52:59::

l9f2.dat
First Record: 124:16:53:00::     Last Record: 124:18:25:47::

There are no lines 10-11.

l12f1.dat
First Record: 125:01:34:51::     Last Record: 125:02:41:08::

l12f2.dat
First Record: 125:02:41:09::     Last Record: 125:03:44:43::

There is no file l12f3.dat.

l12f4.dat
First Record: 125:03:44:44::     Last Record: 125:05:18:25::

l12f5.dat
First Record: 125:05:18:26::     Last Record: 125:05:19:24::

l13f1.dat
First Record: 125:05:19:25::     Last Record: 125:06:19:49::

l13f2.dat
First Record: 125:06:19:50::     Last Record: 125:07:08:57::

l13f3.dat
First Record: 125:07:08:58::     Last Record: 125:07:53:53::

l13f4.dat
First Record: 125:07:53:53::     Last Record: 125:09:27:29::

l14f1.dat
First Record: 125:10:11:20::     Last Record: 125:11:35:18::

l14f2.dat
First Record: 125:11:35:19::     Last Record: 125:12:29:52::

l15f1.dat
First Record: 125:14:12:46::     Last Record: 125:17:59:57::