diff --git a/era/era_dump.cc b/era/era_dump.cc
index a2c82aa..c9e14ad 100644
--- a/era/era_dump.cc
+++ b/era/era_dump.cc
@@ -19,10 +19,12 @@ using namespace std;
 namespace {
 	struct flags {
 		flags()
-			: repair_(false) {
+			: repair_(false),
+			  logical_(false) {
 		}
 
 		bool repair_;
+		bool logical_;
 	};
 
 	//--------------------------------
@@ -40,11 +42,11 @@ namespace {
 
 			if (want_stdout(output)) {
 				emitter::ptr e = create_xml_emitter(cout);
-				metadata_dump(md, e, fs.repair_);
+				metadata_dump(md, e, fs.repair_, fs.logical_);
 			} else {
 				ofstream out(output.c_str());
 				emitter::ptr e = create_xml_emitter(out);
-				metadata_dump(md, e, fs.repair_);
+				metadata_dump(md, e, fs.repair_, fs.logical_);
 			}
 
 		} catch (std::exception &e) {
@@ -61,7 +63,8 @@ namespace {
 		    << "  {-h|--help}" << endl
 		    << "  {-o <xml file>}" << endl
 		    << "  {-V|--version}" << endl
-		    << "  {--repair}" << endl;
+		    << "  {--repair}" << endl
+		    << "  {--logical}" << endl;
 	}
 }
 
@@ -79,6 +82,7 @@ int main(int argc, char **argv)
 		{ "output", required_argument, NULL, 'o' },
 		{ "version", no_argument, NULL, 'V' },
 		{ "repair", no_argument, NULL, 1 },
+		{ "logical", no_argument, NULL, 2 },
 		{ NULL, no_argument, NULL, 0 }
 	};
 
@@ -88,6 +92,10 @@ int main(int argc, char **argv)
 			fs.repair_ = true;
 			break;
 
+		case 2:
+			fs.logical_ = true;
+			break;
+
 		case 'h':
 			usage(cout, basename(argv[0]));
 			return 0;
diff --git a/era/metadata_dump.cc b/era/metadata_dump.cc
index e7eac5f..0d48ebf 100644
--- a/era/metadata_dump.cc
+++ b/era/metadata_dump.cc
@@ -39,6 +39,34 @@ namespace {
 		emitter::ptr e_;
 	};
 
+	class writeset_tree_collator : public writeset_tree_detail::writeset_visitor {
+	public:
+		writeset_tree_collator(map<uint32_t, uint32_t> &exceptions)
+			: exceptions_(exceptions),
+			  current_era_(0) {
+		}
+
+		virtual void writeset_begin(uint32_t era, uint32_t nr_bits) {
+			current_era_ = era;
+		}
+
+		virtual void bit(uint32_t bit, bool value) {
+			if (value) {
+				map<uint32_t, uint32_t>::const_iterator it = exceptions_.find(bit);
+				if (it == exceptions_.end() || it->second < current_era_)
+					exceptions_.insert(make_pair(bit, current_era_));
+			}
+		}
+
+		virtual void writeset_end() {
+		}
+
+	private:
+		map<uint32_t, uint32_t> &exceptions_;
+		uint32_t current_era_;
+	};
+
+
 	struct ignore_writeset_tree_damage : public writeset_tree_detail::damage_visitor {
 		void visit(writeset_tree_detail::missing_eras const &d) {
 		}
@@ -61,16 +89,22 @@ namespace {
 
 	class era_array_emitter : public era_array_visitor {
 	public:
-		era_array_emitter(emitter::ptr e)
-			: e_(e) {
+		era_array_emitter(emitter::ptr e, map<uint32_t, uint32_t> const &exceptions)
+			: e_(e),
+			  exceptions_(exceptions) {
 		}
 
 		virtual void visit(uint32_t index, uint32_t era) {
-			e_->era(index, era);
+			map<uint32_t, uint32_t>::const_iterator it = exceptions_.find(index);
+			if (it != exceptions_.end() && it->second > era)
+				e_->era(index, it->second);
+			else
+				e_->era(index, era);
 		}
 
 	private:
 		emitter::ptr e_;
+		map<uint32_t, uint32_t> exceptions_;
 	};
 
 	struct ignore_era_array_damage : public era_array_detail::damage_visitor {
@@ -90,18 +124,9 @@ namespace {
 			raise_metadata_damage();
 		}
 	};
-}
 
-//----------------------------------------------------------------
-
-void
-era::metadata_dump(metadata::ptr md, emitter::ptr e, bool repair)
-{
-	superblock const &sb = md->sb_;
-
-	e->begin_superblock(to_string(sb.uuid), sb.data_block_size,
-			    sb.nr_blocks,
-			    sb.current_era);
+	void
+	dump(metadata::ptr md, emitter::ptr e, bool repair)
 	{
 		{
 			writeset_tree_emitter visitor(e);
@@ -117,7 +142,8 @@ era::metadata_dump(metadata::ptr md, emitter::ptr e, bool repair)
 
 		e->begin_era_array();
 		{
-			era_array_emitter visitor(e);
+			map<uint32_t, uint32_t> exceptions;
+			era_array_emitter visitor(e, exceptions);
 
 			ignore_era_array_damage ignore;
 			fatal_era_array_damage fatal;
@@ -129,6 +155,57 @@ era::metadata_dump(metadata::ptr md, emitter::ptr e, bool repair)
 		}
 		e->end_era_array();
 	}
+
+	void dump_logical(metadata::ptr md, emitter::ptr e, bool repair)
+	{
+		// This will potentially use a lot of memory, but I don't
+		// see a way around it.
+		map<uint32_t, uint32_t> exceptions;
+
+		{
+			writeset_tree_collator visitor(exceptions);
+
+			ignore_writeset_tree_damage ignore;
+			fatal_writeset_tree_damage fatal;
+			writeset_tree_detail::damage_visitor &dv = repair ?
+				static_cast<writeset_tree_detail::damage_visitor &>(ignore) :
+				static_cast<writeset_tree_detail::damage_visitor &>(fatal);
+
+			walk_writeset_tree(md->tm_, *md->writeset_tree_, visitor, dv);
+		}
+
+		e->begin_era_array();
+		{
+			era_array_emitter visitor(e, exceptions);
+
+			ignore_era_array_damage ignore;
+			fatal_era_array_damage fatal;
+			era_array_detail::damage_visitor &dv = repair ?
+				static_cast<era_array_detail::damage_visitor &>(ignore) :
+				static_cast<era_array_detail::damage_visitor &>(fatal);
+
+			walk_era_array(*md->era_array_, visitor, dv);
+		}
+		e->end_era_array();
+	}
+}
+
+//----------------------------------------------------------------
+
+void
+era::metadata_dump(metadata::ptr md, emitter::ptr e,
+		   bool repair, bool logical)
+{
+	superblock const &sb = md->sb_;
+	e->begin_superblock(to_string(sb.uuid), sb.data_block_size,
+			    sb.nr_blocks,
+			    sb.current_era);
+	{
+		if (logical)
+			dump_logical(md, e, repair);
+		else
+			dump(md, e, repair);
+	}
 	e->end_superblock();
 }
 
diff --git a/era/metadata_dump.h b/era/metadata_dump.h
index 59d9d67..43cf81f 100644
--- a/era/metadata_dump.h
+++ b/era/metadata_dump.h
@@ -7,7 +7,8 @@
 //----------------------------------------------------------------
 
 namespace era {
-	void metadata_dump(metadata::ptr md, emitter::ptr out, bool repair);
+	void metadata_dump(metadata::ptr md, emitter::ptr out,
+			   bool repair, bool logical);
 }
 
 //----------------------------------------------------------------