diff --git a/NEWS b/NEWS
index fdbb5c2..593ba15 100644
--- a/NEWS
+++ b/NEWS
@@ -38,6 +38,9 @@ Unreleased, experimental changes
 
     Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raul Perasso.)
 
+    Better descriptions of countries with same time zone history as
+    Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
+
     Several changes affect tz-link.htm, the main web page.
 
       Mention xCal (Internet RFC 6321) and jCal.
diff --git a/southamerica b/southamerica
index 21a9da8..5391055 100644
--- a/southamerica
+++ b/southamerica
@@ -1676,18 +1676,19 @@ Zone America/Paramaribo	-3:40:40 -	LMT	1911
 Zone America/Port_of_Spain -4:06:04 -	LMT	1912 Mar 2
 			-4:00	-	AST
 
+# These all agree with Trinidad and Tobago since 1970.
 Link America/Port_of_Spain America/Anguilla
 Link America/Port_of_Spain America/Dominica
 Link America/Port_of_Spain America/Grenada
 Link America/Port_of_Spain America/Guadeloupe
-Link America/Port_of_Spain America/Marigot
+Link America/Port_of_Spain America/Marigot	# St Martin (French part)
 Link America/Port_of_Spain America/Montserrat
 Link America/Port_of_Spain America/St_Barthelemy
-Link America/Port_of_Spain America/St_Kitts
+Link America/Port_of_Spain America/St_Kitts	# St Kitts & Nevis
 Link America/Port_of_Spain America/St_Lucia
-Link America/Port_of_Spain America/St_Thomas
+Link America/Port_of_Spain America/St_Thomas	# Virgin Islands (US)
 Link America/Port_of_Spain America/St_Vincent
-Link America/Port_of_Spain America/Tortola
+Link America/Port_of_Spain America/Tortola	# Virgin Islands (UK)
 
 # Uruguay
 # From Paul Eggert (1993-11-18):